As PG:
JS 11, JR 8
OD 14, HA 13
DR 13, PA 14
As SG
JS 15, JR 12
OD 14, HA 13
DR 13, PA 6
These skills are just guidelines. Choosing Peter for U21 will also depend on the generation - if it's bad, the standards are lower and viceversa. But if you train him regularly with 48 min per week and one position where possible, he will be in U21 for sure.